1. Albert-Einstein-Institut www.aei-potsdam.mpg.de Welcome Announcements Goals of this meeting –Review our project –Focus more on science than last time! –Make sure everyone clear about what they are doing, who everyone is –Follow up on various Network duties (Newsletter, web pages, etc…) –Get feedback from advisory board –Make sure our tools (e.g. cactus) are being used Rewards to Johannes Ruoff and Reinhard Prix –Who will help me with notes??? Get all talks on web –Give Peter all ppt, postscript, etc –Scan in your transparencies asap, give us the files Roundtable discussion Saturday afternoon –Review what we came up with –Material for newsletter Organization of student talks/ideas Changes to schedule –Wai-Mo talk –Extended round table

2. Albert-Einstein-Institut www.aei-potsdam.mpg.de What is this project? Seen by us as a Science project –We’ll do much better this time to focus on this Seen by Brussels as a contract to develop young researchers, deliver some milestones –We should see it this way, too! –Especially encourage student and postdocs to help us organize this properly –Develop collaborations, introduce to community, etc Judged by: –Delivering milestones –Papers in collaboration with other groups –Papers involving young researchers –Giving something to the community Training Research Papers Codes for the community

3. Albert-Einstein-Institut www.aei-potsdam.mpg.de This project is not business as usual! It is a contract. –We have deliverables that need to be delivered. –We need to focus our activities to make them happen. It is designed to encourage collaborations. Why? Can do more!! –We have to work extra hard to develop them –We cannot just work as we have been doing in the past. We are doing only “OK”, need to take this meeting to really strengthen our interconnections, develop NEW ones –Computational across all sites –New connections, say between pert and nonlinear, hydro and BH, etc Ask hard questions: –Is group A connecting properly to group B? –If group C is supposed to supply something, are they doing it? –Do people understand their roles? –Are they executing them? Key “deliverables” for this meeting: –Improve this state –Identify weak points, improve on them –Everyone should know: what is expected, when,whom they connect to

4. Albert-Einstein-Institut www.aei-potsdam.mpg.de Other Projects we leverage Astrophysics –NASA Grand Challenge –Astrophysical Simulation Collaboratory (ASC) –Zeus –NASA Round 3 (applied for) Computation –Cactus –TiKSL/GriKSL –ASC –GridLab (we are testbed if funded…) –Grid Forum

5. Albert-Einstein-Institut www.aei-potsdam.mpg.de Major Objectives as stated in our Proposal Formation of a close alliance among the different expert groups to solve urgent GWA problems Development and training of a young community of researchers to populate GWA. Development of Cactus, a community simulation code for relativistic astrophysics, placement in the hands of EU researchers, and training in simulation science. Development of approximation tools: perturbation and post- Newtonian theory, to provide better physical understanding and confirmation of numerical simulations. Application to a set of core astrophysics problems, considered among the most urgent for the detection and interpretation of the first signals seen in the GWA.

6. Albert-Einstein-Institut www.aei-potsdam.mpg.de Specific measures for training as promised Training workshop on the uses of the computational, collaborative and simulation technologies –Do we need more? Exchange researchers for 1-2 week visits, and extended (6 month) exchanges among young researchers (e.g. a numerical postdoc visits a center strong in perturbation theory); –How are we doing? Network meeting every 8 months, where young researchers can present the results of their work; Weekly local group meetings will be coordinated, and when warranted, broadcast by internet video and/or connected by conference telephone calls. –Not doing well on this Internet based video conferencing training courses, (on simulation, perturbation theory, astrophysics theory, etc.) –So far, not done at all: who would take this up?

7. Albert-Einstein-Institut www.aei-potsdam.mpg.de Organisation and Management Managed by the Network Coordinating Scientist at AEI and the Team Leaders of the various groups. A Principal Group designated to manage the progress of each task. –Do you know who/what they are? The Network Steering Committee to meet regularly, through conference telephone calls to assess progress. –Need to do much better on this Advisory Board that will be formed of independent, leading researchers from Europe and abroad. –Welcome and thanks to Jean-Pierre Lasota, Wai-Mo Suen, Sathya, Tsvi Piran, Karsten Danzmann, Bernard Schutz Network will meet every eight months. –When/where next time? Web site maintained at AEI. –Need help! “Project Pages” –Don’t exist…

8. Albert-Einstein-Institut www.aei-potsdam.mpg.de Work Plan Cactus Nonlinear BH simulations Hydrodynamics Post-Newtonian theory Stellar perturbation theory Perturbative time evolutions Asymptotic Wave Codes Training complete, AMR tested 12 months24 months36 months Remote/distributed Simulations, input from projects below Full CCM matching Module for Cactus Full community Code release, with documentation Merger simulations with studies of waves Continually refined as techniques developed Completed binary NS Initial Data Module Simulations refined as techniques developed Accretion Code Asymptotic waves, CCM matching PN GW, reaction expressions Post-N.Hydro Code, Post-N Initial Data Module Simulations continue Pert Eqs. for rotating NS, nonlinear results Modes computed, valuable input to num. simulations Close limit module, time evolution for rotating NSs Perturbative evolutions, Input to num. simulations Nonlinear Numerical Codes, Simulations Pert. Techniques, codes, Time

9. Albert-Einstein-Institut www.aei-potsdam.mpg.de Project Coordinators Do you know who they are? Watch over your groups Go to various groups to give talks Write contribution to a newsletter, helping us build material for reports (due in October) Develop meeting/coordination schedule Use web site to help organize the projects Review organization/project plan –Each coordinator to discuss status in their area –Then go through room Introductions: welcome Make sure everyone connected to some group!

10. Albert-Einstein-Institut www.aei-potsdam.mpg.de Schedule and Milestones A. Fully nonlinear numerical evolutions –a.1 Continued development of CACTUS, with training (ED) Training in the use of the Cactus code for the entire Network (all teams, 12 months). Incorporation of more efficient elliptic solvers into Cactus (AEI, UIB, 24 months). Continued testing of algorithms of adaptive mesh refinement (AMR) provided by DAGH (AEI, UIB, 24 months). (SCOTT HAWLEY) Extension of remote and distributed computing capabilities (Gigabit project) for Network use (AEI, 24 months). Refinement of evolution methods and formulation of equations (AEI, UIB, ongoing). Refinement of general relativistic hydro-dynamical algorithms (UVEG, ongoing) (JOSE-MARIA IBAÑEZ). Development of appropriate gauge conditions for stable numerical evolutions (AEI, OP, UIB, AUTH, FSU, ongoing). (BERND BRÜGMANN)

11. Albert-Einstein-Institut www.aei-potsdam.mpg.de –a.2. Vacuum BH evolutions (ED) Continued studies of 3D, grazing BH mergers and extraction of waveforms and other physics; comparison with perturbation theory (AEI, UIB, ongoing). Development of BH excision techniques for long term stability of orbiting BH’s (AEI, UIB, ongoing). (MIGUEL ALCUBIERRE) Studies of distorted rotating BH’s, modeling the late stages of BH coalescence; perturbative comparisons (AEI, UIB, 24 months). –a.3. Fully nonlinear GR hydrodynamics (ERIC GOURGOULHON) Study of GW’s from stable/unstable NS models; comparison with perturbation theory (AEI, OP, URLSDF, UPHEC, SOTON, AUTH, SISSA, ongoing). (NICK STERGIOULAS) Study of GW from merging binary NS models; comparison with perturbation theory in post-Newtonian and close limit approximation where appropriate (AEI, FSU, OP, UPHEC, SOTON, AUTH, SISSA, ongoing). (LUCIANO REZZOLLA) Development of numerical code to study the dynamical behavior of the accretion torus expected to form outside a Kerr BH formed after the merger of two massive NS (AEI, SISSA, Valencia, 24 months). (JOHN MILLER) Development of relativistic binary NS initial data for Cactus (OP, AEI, 12 months). (ERIC)

12. Albert-Einstein-Institut www.aei-potsdam.mpg.de –a.4. Development of asymptotic gravitational wave codes. (RAY D’INVERNO) Development of a mechanism for analyzing asymptotic wave-forms for any fully relativistic 3+1 code on a finite grid (AEI, SOTON, OP, 24 months). (ED) Further development, testing and evaluation of 3D Cauchy- characteristic matching (CCM) techniques for matching and interior Cauchy 3+1 region and an exterior characteristic region (SOTON, AEI, UPHEC, 24 months). (RAY) Development of a general exterior CCM module for Cactus (SOTON, AEI, UVEG, UPHEC, 36 months). (We will drop this) Characteristic Hydro: investigate its use for numerical relativity (PHILIP PAPADAPOULOS: NEW)

13. Albert-Einstein-Institut www.aei-potsdam.mpg.de B. Approximation studies –b.1. Post-Newtonian schemes for numerical relativity. (GERHARD SCHAEFFER) Reformulation of first post-Newtonian analytical GW wave form expressions, useful for numerical calculations (OP, FSU, 12 months). Derivation of first post-Newtonian radiation damping in a form useful for numerical implementation (OP, FSU, 12 months). Numerical implementation of the above as module in Cactus, including advanced equations of state, to study the collapse of rotating evolved stellar cores, and the initial stages of merging NS binaries (SISSA, SOTON, AEI, 24 months). Reformulation of the fully relativistic initial value problem to account for post-Newtonian physics input (OP, FSU, 24 months). (PETER DIENER)

14. Albert-Einstein-Institut www.aei-potsdam.mpg.de –b.2. Relativistic stellar perturbation theory. (NILS ANDERSSON) Derivation of ideal formulation of the perturbation equations for a rapidly rotating star; formulation of pulsation mode-problem for rotating configurations; exhaustive studies of the modes of rotating NS.(AUTH, URLSDF, UPHEC, SISSA, 24 months). Study of modes that can become unstable in rotating NS’s, in particular the recently discovered r-mode instability; improved understanding of the role of such instabilities; potential detectability of associated GW critically assessed (SOTON, AUTH, AEI, SISSA, ongoing). Further development of perturbative techniques to infer detailed information about GW sources i.e. mass, radius, rotational rate and, in the case of NS, the equation of state of the final object (AUTH, SOTON, URLSDF, ongoing). Derivation of non-linear perturbation equations for non-rotating stars to assess the linear perturbation theory for NS; comparison with Cactus (UPHEC, SISSA, 24 months) (PHILIPPOS).

15. Albert-Einstein-Institut www.aei-potsdam.mpg.de –b.3 Perturbative time-evolutions. (KOSTAS KOKKOTAS) Development of perturbation equations for slowly rotating stars for a numerical time evolution. Generic initial data will then be evolved, with special focus on the various pulsation modes of the system (AUTH, SOTON, 24 months). Derivation of the time-dependent perturbation equations for rapidly rotating stars, and numerical implementation of these equations (AUTH, OP, ongoing). Improvement of earlier work on perturbation evolution on a collapsing background; extension to slow rotation; numerical code to compute GW emitted by specific models of collapsing stars. Emphasis on the study of oscillations of the compact objects (NS or BH) that form from collapse. (URLSDF, AEI, UPHEC, SISSA, ongoing). (CARSTEN GUNDLACH) Further development of Zerilli and Teukolsky-based perturbation formalisms to evolve rotating-merging BH and NS systems (close limit approximation), to interpret and confirm fully numerical simulations. Matching procedure developed to extend previously evolved nonlinear simulations in perturbative regime (AEI, SOTON, AUTH, 24 months). (ED)

16. Albert-Einstein-Institut www.aei-potsdam.mpg.de Miscellaneous Organizational Communication –Video Conferencing –Phone Calls –Travel (can use AEI as a central meeting place) –Should exchange researchers –Cactus and docs… Web Site: Need more help –Peter Diener, Johannes Ruoff, Ed handling local pages –New features needed General project descriptions missing Description of each working group, and membership, contact info Paper repository, comment page Annotated Bibliography of previous relevant group papers PR Public outreach –Project pages: how to do them right? –Coordinators: use this to coordinate! Have an active set of pages! –When can meet this week to discuss this, who will come?

17. Albert-Einstein-Institut www.aei-potsdam.mpg.de Student/Postdoc representation –Special meetings? E.g., this week… –Representatives in our organizational meetings? –Questions? –Does everyone have a clear role yet? Graphics –May be able to help from AEI/ZIB for special cases –Good for magazine covers, etc! Computer time: who needs accounts somewhere? Review notes from last meeting (do this every time) –Find it on web site (how many of you have looked at it?) –How did we do on each item?

18. Albert-Einstein-Institut www.aei-potsdam.mpg.de Meetings to Organize this Week Various Project meetings –Time dependent per theory, NS-NS collisions, accretion, etc –Coordinators, Coordinate! –Round table Sunday to report/discuss Student/Postdoc meeting –Get to know each other, know your project area coordinators –Discuss things you want out of this (meetings, talk schedules, special lectures, school, etc –What you need to be productive, know what is going on… –Talk debriefing, FAQ on web –Let us know at round table at end Cactus training –Get together, get things running

19. Albert-Einstein-Institut www.aei-potsdam.mpg.de Extra Roundtable at end of week Are we doing OK? What do we do next week, next month, next year for this project? Are we on target with physics? What other physics projects should we consider? (e.g. strange stars…) How do we publicize our project? How and when do we deliver codes to community? Student/postdoc input on project? –Are you getting what you need? –Are you clear about what is happening? –What are you goals for next week, next year? –What would you like to see in the next meeting?